studies are under way to determine effectiveness of the various structure 

 components. A report "Behavior of Beach Fill and Borrow Area at Prospect 

 Beach, West Haven, Connecticut" has been prepared (Technical Memorandum 

 No. 127). This report analyzes comparative survey and sample data to 

 determine the behavior of beach fill obtained from an offshore borrow 

 source. Beach fill projects in Connecticut (other than Prospect Beach), 

 New Jersey, Delaware, Florida, Pennsylvania and California were under study 

 this fiscal year. 



(m) Experimental Studies of the Effectiveness of Sand Fences. 



In cooperation with the State of North Carolina and the Wilmington 

 District of the Corps of Engineers a study has been initiated on Core Bank, 

 one of the Outer Banks of North Carolina, on the effectiveness of various 

 types of sand fence in building and stabilizing dunes. A series of 1,000- 

 foot sections of various types and arrangements of sand fence have been 

 installed on Core Bank, and periodic examinations and surveys are made to 

 obtain information on the comparative effectiveness of the various sections, 

 A self-contained wind measuring instrument has been installed in the test 

 area to obtain information on wind velocity during the experiment. 



(n) Model Determination, Scour at Toe of Seawalls. 



A study has been initiated in the Shore Processes Test Basin in an 

 attempt to experimentally relate the depth and lateral extent of scour at 

 the toe of seawalls to incident wave and beach sediment characteristics. 

 Waves are generated perpendicular to a vertical seawall located initially 

 at the still water level, and the development of the scour hole is measured. 

 Several wave conditions have now been tested for two sand sizes (0.2 and 

 0.4-mm median diameter). Although the program has involved so far only a 

 vertical wall, located at the still water level, other types of walls and 

 locations relative to still water level are planned for future tests. 



(o) Hurricane Studies. 



The staff of the Board has continued to support the hurricane study 

 work of the Corps of Engineers. Considerable work has been done by the 

 staff in developing and improving simplified methods for estimating storm 

 surge elevations and wave heights under a variety of shoreline conditions. 

 Wave forces, and wave run-up and overtopping phenomena connected with sea- 

 wall, dike, and barrier design under hurricane conditions have also been 

 studied. A generalized study of the effect of offshore slope on the amount 

 of wave set-up observed with high hurricane waves has continued. The test 

 results have been summarized in a report "Experimental Determination of 

 Wave Set-up" delivered at the 2nd Technical Conference on Hurricanes at 

 Miami Beach, Florida. In general the tests have indicated a wave set-up 

 at the shore line of about 10 to 15 percent of the wave height for beach 

 profiles of 1 on 15 slope and less, with little or no set-up at the shore 

 line for slopes steeper than about 1 on 6. A number of tests have also 



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